1. Field of the Invention
The present invention relates to a turret punch press having upper and lower turrets for holding a plurality of punches and dies each for performing punching in a plate workpiece.
2. Prior Art
A turret punch press generally includes an upper turret for holding punches and a lower turret for holding dies. The upper and lower turrets are vertically disposed to face each other with a certain gap therebetween and are synchronously turned to locate a required pair of punch and die at a punching position under a striker.
In order to exchange the dies on the turrets, the dies must be transferred through the gap between the upper and lower turrets which is usually very small. Accordingly, the maximum height of the die is limited by the width of the gap. Furthermore, in a conventional turret punch press, it is difficult to exchange the dies on an automatic index station since the dies on the automatic index station are held in rotary holders; in other words, in order to exchange the dies on the automatic index station, a suitable die passage must be provided in the side wall of the rotary holders.